U.S. Sen. Bill Nelson saidhe fears Russia's aggressive action against Georgia may have some seriousconsequences on the American space program.

If Russia fails to holdback military action in the former Soviet republic, it could hurt U.S. chancesof accessing the International Space Station once NASA retiresthe space shuttles in 2010, the Democrat from Orlando said Tuesday.

The Russian Soyuz vehiclewill be the only option available for NASA to send crew and cargo to the spacestation until the shuttle'sreplacement becomes available for manned missions in 2015. Nelson fearsdeteriorating U.S.-Russia politics may result in "Russia denying us ridesor charging exorbitant amounts for them."

NASA's agreement to purchase rideson the Soyuz came about from a waiver Congress granted the agency from theIran-Syria Non-Proliferation Act. The law prohibits the United States frombuying space-related goods and services from Russia while that nation exportsnuclear technology to Iran.

NASA's waiver from the banexpires in 2011. Nelson fears that recent developments between Russia andGeorgia may make it hard for lawmakers to extend the exemption.

"It was a tough sellbefore, but it was doable simply because we didn't have a choice. We don't wantto deny ourselves access to the space station, the very place we have built andpaid," Nelson said. "It's going to be a tougher sell now unless thereare critical developments during the next 48 to 72 hours."

"If I were presidentI'd be pulling out all the stops to get Russia to understand the consequencesof continued bad behavior," said Nelson, who just returned from a trip toAfghanistan with Senate Majority Leader Harry Reid and other lawmakers.